Search Results (61)

In order to solve the problems of stress concentration in the roadway peripheral rock and poor support effect in a wide range of high-stress areas under the high-stress environment of MaKeng Iron Mine, this study is based on the theory of loose circle support, combined with the calculation of the anchor suspension theory to determine the reasonable length of pipe slit anchors and other key parameters. Through the two methods of punching and bonding, we examined the destructive effect to determine the thickness of the spray concrete and, finally, put forward the pipe slit anchor mesh spraying support technology program. The numerical model was constructed by using three-dimensional numerical simulation software (FLAC3D 5.0), and the support effect analysis of the support scheme was carried out systematically. The research results show the following: under the high-stress environment dominated by external horizontal tectonic stress, the use of pipe slit anchor net spray support technology can significantly improve the distribution characteristics of the plastic zone, stress field and displacement around the roadway; after the support, the deformation and displacement of the surrounding rock around the empty zone are significantly reduced, effectively preventing the destruction of the surrounding rock under the high-stress environment. The program not only unifies the mine support form and support parameters but also specifies the support construction method and construction quality inspection standard, which provides a scientific technical guarantee for mine shaft support and has an important reference value for the support design and construction of a mine roadway under a similar high-stress environment. Full article

Electrocatalytic water splitting is a promising approach for obtaining clean hydrogen energy. In this work, novel molybdate@carbon paper composite electrocatalysts (CoxFe10-xMoO@CP), displaying outstanding electrocatalytic capabilities, were deriving from anchoring cobalt/iron molybdate materials onto the surface of carbon paper fibers. By adjusting the cobalt-to-iron ratio, the composite (Co5Fe5MoO@CP), with the optimal molar proportion (Co/Fe = 5/5), exhibited a distinctive nanoflower morphology (50–100 nm), which provided a significant number of active sites for electrocatalytic reactions, and showed the strongest electrocatalytic potency for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Specifically, the overpotentials for HER and OER were 123.6 and 245 mV at 10 mA·cm⁻², with a Tafel slope of 78.3 and 92.2 mV·dec⁻¹, respectively. The hydrogen and oxygen evolution reactions remained favorable and stable over 35 days and 2 weeks of cyclic voltammetry cycles. In a two-electrode system, efficient overall water splitting was achieved at a cell voltage of 1.60 V. Under high alkaline concentration and temperature conditions, the Co5Fe5MoO@CP composite still maintained excellent HER and OER catalytic activity and stability, indicating its satisfactory potential for industrial applications. Density functional theory (DFT) analysis revealed that the promoted hydrogen evolution capability derived from the synergistic catalytic effect of iron and cobalt atoms within the molecule, while cobalt atoms functioned as the catalytic core for the oxygen evolution process. This work provides a novel strategy towards high-efficiency electrocatalysts to significantly accelerate the overall water splitting. Full article

Developing highly active and durable non-noble metal catalysts is crucial for energy conversion and storage, especially for proton exchange membrane fuel cells (PEMFCs) and lithium-oxygen (Li-O₂) batteries. Non-noble metal catalysts are considered the greatest potential candidates to replace noble metal catalysts in PEMFCs and Li-O₂ batteries. Herein, we propose a novel type of non-noble metal catalyst (Fe-Hf/N/C) doped with Hf into a mesoporous carbon material derived from Hf-ZIF-8 and co-doping with Fe and N, which greatly enhanced the activity and durability of the catalyst. When applied in the cathode of PEMFCs, the current density can reach up 1.1 and 1.7 A cm⁻² at 0.7 and 0.6 V, respectively, with a maximum power density of 1.15 W cm⁻². The discharge capacity of the Li-O₂ batteries is up to 15,081 mAh g⁻¹ with Fe-Hf/N/C in the cathode, which also shows a lower charge overpotential, 200 mV lower than that of the Fe/N/C. Additionally, the Fe-Hf/N/C catalyst has demonstrated better stability in both PEMFCs and Li-O₂ batteries. This reveals that Hf can not only optimize the electronic structure of iron sites and increase the active sites for the oxygen reduction reaction, but can also anchor the active sites, enhancing the durability of the catalyst. This study provides a new strategy for the development of high-performance and durable catalysts for PEMFCs and Li-O₂ batteries. Full article

The roadway project of broken rock mass in the Shilu Iron Deposit was taken as the research object to discuss the stability control of the surrounding rocks using support patterns with broken rock mass. The grade evaluation of rock mass quality was conducted based on the geomechanical classification of rock mass. The roadway support effect in broken rock mass was calculated. Then, the section convergence characteristics of roadway surrounding rocks were analyzed under the current support scheme using displacement monitoring technology. The conclusions were described as follows: (1) The surrounding rock integrity of the No.6 and No.7 transportation roadways in the middle section of the Baoxiu mining area (Level 120) is poor. Based on geological survey data and rock mass classification, the rock mass quality in this region has been rated as Class IV. The joint support pattern of the anchor net and shotcrete was used according to the support guidelines. (2) The parameters for the support structure within Shilu Iron Deposit were designed, according to the requirements, as follows: the use of Portland cement; a shotcrete thickness of 55 mm; resin bolts with a minimum outer diameter of φ 20 mm and a length of 2200 mm; and row and column spacings of 1100 mm each. Meanwhile, a rectangular metal mesh of 80 × 80 mm was used as the anchor mesh. (3) The cross-section displacement reached 20 mm within a week using the support pattern according to displacement monitoring results of the on-site roadway section. Moreover, the convergence deformation rate significantly changed. However, the rate rapidly decreased after the first week, and the cross-section showed no further deformation after one month. The support pattern could control the displacement of surrounding rocks, which was verified by the monitoring results. Full article

The prestressed active reinforcement of concrete structures using iron-based shape memory alloys (Fe-SMAs) is investigated in this experimental study through three connecting methods: adhesive–bolted hybrid connection, bolted connection, and adhesively bonded connection by activating at elevated temperatures (heating and cooling) and constraining deformation to generate prestress inside Fe-SMAs, through which compressive stress is generated in the parent concrete structures. In tests, the Fe-SMA is activated at 250 °C using a hot air gun, generating a prestress of 184.6–246 MPa. The experimental results show that local stress concentration in the concrete specimen and Fe-SMA plate around the hole is caused by the bolted connection. The adhesively bonded connection is prone to softening and slip of the structural adhesive during the activation process, thereby reducing the overall recovery force of Fe-SMAs. The adhesive–bolted hybrid connection effectively mitigates the local stress concentration problem of concrete and Fe-SMAs at anchor holes, while avoiding the prestress loss caused by the softening and slip of structural adhesive during elevated-temperature activation, achieving good reinforcement effect. This study on the connection methods of an Fe-SMA for reinforcing concrete structures provides both experimental support and practical guidance for its engineering application, offering new perspectives for future research. Full article

The Industrial Metrology Business Unit of Nikon Corporation, on behalf of ScottishPower Renewables and Maritime Archaeology (MA), Southampton, UK, has employed X-ray CT (computed tomography) to visualise the internal structure of an anchor found in the North Sea. The non-destructive method of internal inspection and measurement has helped to determine approximately when it was made. The results indicate that the artefact, initially thought to be potentially Roman, is probably more recent, likely dating to between the late 16th and early 17th centuries CE. This paper presents the discovery, recovery, analysis and interpretation of a significant find from a UK offshore wind farm and underscores the valuable role that non-destructive X-ray CT played in the investigation. Full article

The employment of the maritime medium by Southern Levantine societies is examined here through its engagement with coastline facilitation and the building of artificial harbors where natural bays are insufficient or non-existent. The development and availability of technologies and methods are surveyed and analyzed vis-à-vis local choices made to adopt or to reject mediating tools such as jetties, quays, and breakwaters. The article discusses technological and conceptual innovations against the background of long-term practices, essentially in favor of natural features. Despite the early adoption of emerging technologies by such exemplars as Iron Age Atlit, Hellenistic Akko-Ptolemaïs, or Roman Caesarea, the rest of the Southern Levant did not join in, and Caesarea, Akko-Ptolemaïs, and Atlit fell short of maintaining their facilities in the long term. The solution for ships was found instead in natural anchorages and, much more dominantly, in the beaching of smaller vessels and offshore anchoring of larger ones. Full article

By virtue of the high theoretical energy density and low cost, Lithium–sulfur (Li-S) batteries have drawn widespread attention. However, their electrochemical performances are seriously plagued by the shuttling of intermediate polysulfides and the slow reaction kinetics during practical implementation. Herein, we designed a freestanding flexible membrane composed of nitrogen-doped porous carbon nanofibers anchoring iron and zinc single atoms (FeZn-PCNF), to serve as the polysulfide barrier and the reaction promotor. The flexible porous networks formed by the interwoven carbon nanofibers not only offer fast channels for the transport of electrons/ions, but also guarantee the structural stability of the all-in-one multifunctional interlayer during cycling. Highly dispersed Fe and Zn atoms in the carbon scaffold synergistically immobilize sulfur species and expedite their reversible conversion. Therefore, employing FeZn-PCNF as the freestanding interlayer between the cathode and separator, the Li-S battery delivers a superior initial reversible discharge capacity of 1140 mA h g⁻¹ at a current density of 0.5 C and retains a high capacity of 618 mA h g⁻¹ after 600 cycles at a high current density of 1 C. Full article

Background and aim: We conducted a review to determine the efficacy of amlodipine alongside iron chelators on serum ferritin levels and liver T2-weighted magnetic resonance imaging (MRI T2*) in β-thalassemia patients. Methods: Systematic search was conducted in multiple databases, including Web of Science, PubMed, Scopus, Embase, Cochrane Library, ClinicalTrials.gov, the Iranian Registry of Clinical Trials (IRCT), ProQuest, OpenGrey, and Web of Science Conference Proceedings Citation Index. The search was closed in January 2023. Primary outcomes were comprised of liver MRI T2* (millisecond (msec)) and serum ferritin levels (ng/mL). Results: Seven studies (n = 227) were included in the study. The pooled Cohen’s d for serum ferritin was estimated at −0.46, 95% confidence interval (CI) −1.11 to 0.19 and p = 0.16 (I² 86.23%, p < 0.0001). The pooled mean difference for serum ferritin was −366.44 ng/mL, 95% CI −844.94 to 112.05, and p = 0.13 (I² 81.63%, p < 0.0001). After a meta-regression based on the length of using amlodipine, a coefficient for the mean difference was also −23.23 ng/mL and 95% CI −155.21 to 108.75. The coefficient obtained from a meta-regression as per the amlodipine dose at 5 mg/day than 2.5 to 5 mg/day anchored at −323.49 ng/mL and 95% CI −826.14 to 1473.12. A meta-regression according to the baseline values of serum ferritin discovered a coefficient of 1.25 ng/mL and 95% CI 0.15 to 2.35. Based on two included studies (n = 96), the overall Cohen’s d for liver MRI T2* was 2.069, 95% CI −0.896 to 5.035, and p = 0.17 (I² 96.31%, p< 0.0001). The synthesized mean difference for liver MRI T2* was 8.76 msec, 95% CI −4.16 to 21.67, and p = 0.18 (I² 98.38%, p < 0.000). Conclusion: At a very low level of evidence, probably using amlodipine at a dose of 2.5 to 5 mg a day, up to a year, alongside iron chelators slightly decreases serum ferritin levels in iron-overloaded thalassemia cases by nearly 366 ng/mL (23 ng/mL per month). The liver MRI T2* might also rise to 8.76 msec upon co-therapy with amlodipine. Full article

Photocatalytic coatings are difficult to obtain on textile materials because of the sometimes contradictory properties that must be achieved. In order to obtain a high efficiency of a photocatalytic effect, the metal–oxide semiconductor must be found in the vicinity of the coating–air interface in order to come into direct contact with the contaminant species and allow light radiation access to its surface. Another necessary condition is related to the properties of the covering textile material as well as to the stability of the xerogel films to light and wet treatments. In this sense, we proposed a solution based on hybrid silica films generated by sol–gel processes, coatings that contain as a photocatalyst TiO₂ sensitized with tetracarboxylic acid of iron (III) phthalocyanine (FeTCPc). The coatings were made by the pad–dry–cure process, using in the composition a bifunctional anchoring agent (3-glycidoxipropyltrimethoxysilane, GLYMO), a crosslinking agent (sodium tetraborate, BORAX), and a catalyst (N-methylimidazole, MIM) for the polymerization of epoxy groups. The photodegradation experiments performed on methylene blue (MB), utilized as a model contaminant, using LED or xenon arc as light sources, showed that the treatment with BORAX improves the resistance of the coatings to wet treatments but worsens their photocatalytic performances. Full article

This paper proposes a different strategy for deriving carbon materials from biomass, abandoning traditional strong corrosive activators and using a top−down approach with a mild green enzyme targeted to degrade the pectin matrix in the inner layer of pomelo peel cotton wool, inducing a large number of nanopores on its surface. Meanwhile, the additional hydrophilic groups produced via an enzymatic treatment can be used to effectively anchor the metallic iron atoms and prepare porous carbon with uniformly dispersed Fe−N_x structures, in this case optimizing sample PPE−FeNPC−900’s specific surface area by up to 1435 m² g⁻¹. PPE−FeNPC−900 is used as the electrode material in a 6 M KOH electrolyte; it manifests a decent specific capacitance of 400 F g⁻¹. The assembled symmetrical supercapacitor exhibits a high energy density of 12.8 Wh kg⁻¹ at a 300 W kg⁻¹ power density and excellent cycle stability. As a catalyst, it also exhibits a half−wave potential of 0.850 V (vs. RHE) and a diffusion-limited current of 5.79 mA cm⁻² at 0.3 V (vs. RHE). It has a higher electron transfer number and a lower hydrogen peroxide yield compared to commercial Pt/C catalysts. The green, simple, and efficient strategy designed in this study converts abundant, low−cost waste biomass into high-value multifunctional carbon materials, which are critical for achieving multifunctional applications. Full article

Coal flow in belt conveyors is often mixed with foreign objects, such as anchor rods, angle irons, wooden bars, gangue, and large coal chunks, leading to belt tearing, blockages at transfer points, or even belt breakage. Fast and effective detection of these foreign objects is vital to ensure belt conveyors’ safe and smooth operation. This paper proposes an improved YOLOv5-based method for rapid and low-parameter detection and recognition of non-coal foreign objects. Firstly, a new dataset containing foreign objects on conveyor belts is established for training and testing. Considering the high-speed operation of belt conveyors and the increased demands for inspection robot data collection frequency and real-time algorithm processing, this study employs a dark channel dehazing method to preprocess the raw data collected by the inspection robot in harsh mining environments, thus enhancing image clarity. Subsequently, improvements are made to the backbone and neck of YOLOv5 to achieve a deep lightweight object detection network that ensures detection speed and accuracy. The experimental results demonstrate that the improved model achieves a detection accuracy of 94.9% on the proposed foreign object dataset. Compared to YOLOv5s, the model parameters, inference time, and computational load are reduced by 43.1%, 54.1%, and 43.6%, respectively, while the detection accuracy is improved by 2.5%. These findings are significant for enhancing the detection speed of foreign object recognition and facilitating its application in edge computing devices, thus ensuring belt conveyors’ safe and efficient operation. Full article

Adipose tissue is a crucial organ in energy metabolism and thermoregulation. Adipose tissue phenotype is controlled by various signaling mechanisms under pathophysiological conditions. Type II transmembrane serine proteases (TTSPs) are a group of trypsin-like enzymes anchoring on the cell surface. These proteases act in diverse tissues to regulate physiological processes, such as food digestion, salt-water balance, iron metabolism, epithelial integrity, and auditory nerve development. More recently, several members of the TTSP family, namely, hepsin, matriptase-2, and corin, have been shown to play a role in regulating lipid metabolism, adipose tissue phenotype, and thermogenesis, via direct growth factor activation or indirect hormonal mechanisms. In mice, hepsin deficiency increases adipose browning and protects from high-fat diet-induced hyperglycemia, hyperlipidemia, and obesity. Similarly, matriptase-2 deficiency increases fat lipolysis and reduces obesity and hepatic steatosis in high-fat diet-fed mice. In contrast, corin deficiency increases white adipose weights and cell sizes, suppresses adipocyte browning and thermogenic responses, and causes cold intolerance in mice. These findings highlight an important role of TTSPs in modifying cellular phenotype and function in adipose tissue. In this review, we provide a brief description about TTSPs and discuss recent findings regarding the role of hepsin, matriptase-2, and corin in regulating adipose tissue phenotype, energy metabolism, and thermogenic responses. Full article

The expression and methylation of promoters of the genes encoding succinate dehydrogenase, fumarase, and NAD-malate dehydrogenase in maize (Zea mays L.) leaves depending on the light regime were studied. The genes encoding the catalytic subunits of succinate dehydrogenase showed suppression of expression upon irradiation by red light, which was abolished by far-red light. This was accompanied by an increase in promoter methylation of the gene Sdh1-2 encoding the flavoprotein subunit A, while methylation was low for Sdh2-3 encoding the iron-sulfur subunit B under all conditions. The expression of Sdh3-1 and Sdh4 encoding the anchoring subunits C and D was not affected by red light. The expression of Fum1 encoding the mitochondrial form of fumarase was regulated by red and far-red light via methylation of its promoter. Only one gene encoding the mitochondrial NAD-malate dehydrogenase gene (mMdh1) was regulated by red and far-red light, while the second gene (mMdh2) did not respond to irradiation, and neither gene was controlled by promoter methylation. It is concluded that the dicarboxylic branch of the tricarboxylic acid cycle is regulated by light via the phytochrome mechanism, and promoter methylation is involved with the flavoprotein subunit of succinate dehydrogenase and the mitochondrial fumarase. Full article

In environmental and agronomic settings, even minor imbalances can trigger a range of unpredicted responses. Despite the widespread use of metal-based nanoparticles (NPs) and new bio-nanofertilizers, their impact on crop production is absent in the literature. Therefore, our research is focused on the agronomic effect of spray application of gold nanoparticles anchored to SiO₂ mesoporous silica (AuSi-NPs), zinc oxide nanoparticles (ZnO-NPs), and iron oxide nanoparticles (Fe₃O₄-NPs) on sunflowers under real-world environments. Our findings revealed that the biosynthetically prepared AuSi-NPs and ZnO-NPs were highly effective in enhancing sunflower seasonal physiology, e.g., the value of the NDVI index increased from 0.012 to 0.025 after AuSi-NPs application. The distribution of leaf trichomes improved and the grain yield increased from 2.47 t ha⁻¹ to 3.29 t ha⁻¹ after ZnO-NPs application. AuSi-NPs treatment resulted in a higher content of essential linoleic acid (54.37%) when compared to the NPs-free control (51.57%), which had a higher determined oleic acid. No NPs or residual translocated metals were detected in the fully ripe sunflower seeds, except for slightly higher silica content after the AuSi-NPs treatment. Additionally, AuSi-NPs and NPs-free control showed wide insect biodiversity while ZnO-NPs treatment had the lowest value of phosphorus as anti-nutrient. Contradictory but insignificant effect on physiology, yield, and insect biodiversity was observed in Fe₃O₄-NPs treatment. Therefore, further studies are needed to fully understand the long-term environmental and agricultural sustainability of NPs applications. Full article